Call libusb_init on the FILE thread.

Call libusb_init on the FILE thread.

On some platforms this function creates an initial enumeration of
devices which can cause jank when done on the UI thread.

BUG=645583
Committed: https://crrev.com/20dbee333a778a90bd8966a7a5227d3cb4592e5d
Cr-Commit-Position: refs/heads/master@{#437382}

[Reilly Grant (use Gerrit), 2016-12-08 02:18:58]

The CQ bit was checked by reillyg@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-08 02:19:35]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Reilly Grant (use Gerrit), 2016-12-08 02:20:31]

reillyg@chromium.org changed reviewers:
+ juncai@chromium.org

[Reilly Grant (use Gerrit), 2016-12-08 02:20:32]

Please take a look.

[commit-bot: I haz the power, 2016-12-08 03:26:35]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-08 03:26:38]

Dry run: This issue passed the CQ dry run.

[juncai, 2016-12-08 20:00:40]

LGTM.

https://codereview.chromium.org/2557073004/diff/1/device/usb/usb_service_impl.h
File device/usb/usb_service_impl.h (right):

https://codereview.chromium.org/2557073004/diff/1/device/usb/usb_service_impl...
device/usb/usb_service_impl.h:89: bool usb_unavailable_ = false;
nit: maybe change the variable name to be:
bool usb_available_ = true;

[Reilly Grant (use Gerrit), 2016-12-08 22:44:33]

The CQ bit was checked by reillyg@chromium.org

[Reilly Grant (use Gerrit), 2016-12-08 22:44:39]

https://codereview.chromium.org/2557073004/diff/1/device/usb/usb_service_impl.h
File device/usb/usb_service_impl.h (right):

https://codereview.chromium.org/2557073004/diff/1/device/usb/usb_service_impl...
device/usb/usb_service_impl.h:89: bool usb_unavailable_ = false;
On 2016/12/08 at 20:00:39, juncai wrote:
> nit: maybe change the variable name to be:
> bool usb_available_ = true;

The reason I named this usb_unavailable_ is because until we see if we can
initialize context_ we don't know if USB will be available or not, so it seemed
less surprising to have a variable that becomes true only when we've given up on
initializing USB than a variable that it true before we've even tried.

[commit-bot: I haz the power, 2016-12-08 22:45:12]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-08 22:52:07]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1481237073876740, "parent_rev":
"ff321926141b204dda8c53e91cbdf5af8bf16321", "commit_rev":
"c55763d5c51d62183793375483b23a2f5e5b215f"}

[commit-bot: I haz the power, 2016-12-08 22:52:36]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-08 22:55:20]

Description was changed from

==========
Call libusb_init on the FILE thread.

On some platforms this function creates an initial enumeration of
devices which can cause jank when done on the UI thread.

BUG=645583
==========

to

==========
Call libusb_init on the FILE thread.

On some platforms this function creates an initial enumeration of
devices which can cause jank when done on the UI thread.

BUG=645583

Committed: https://crrev.com/20dbee333a778a90bd8966a7a5227d3cb4592e5d
Cr-Commit-Position: refs/heads/master@{#437382}
==========

[commit-bot: I haz the power, 2016-12-08 22:55:21]

Patchset 1 (id:??) landed as
https://crrev.com/20dbee333a778a90bd8966a7a5227d3cb4592e5d
Cr-Commit-Position: refs/heads/master@{#437382}

[juncai, 2016-12-08 23:02:11]

https://codereview.chromium.org/2557073004/diff/1/device/usb/usb_service_impl.h
File device/usb/usb_service_impl.h (right):

https://codereview.chromium.org/2557073004/diff/1/device/usb/usb_service_impl...
device/usb/usb_service_impl.h:89: bool usb_unavailable_ = false;
On 2016/12/08 22:44:39, Reilly Grant wrote:
> On 2016/12/08 at 20:00:39, juncai wrote:
> > nit: maybe change the variable name to be:
> > bool usb_available_ = true;
> 
> The reason I named this usb_unavailable_ is because until we see if we can
> initialize context_ we don't know if USB will be available or not, so it
seemed
> less surprising to have a variable that becomes true only when we've given up
on
> initializing USB than a variable that it true before we've even tried.

I see. Thanks for the explanation.